Refrigerant compressor



July 13, 1943. w. E. SHORE 2,324,434

I REFRIGERANT COMPRESSOR I Filed March 29, 1940 4 sheets-sheet 1 1/. I nvehtor.

\Afi/liam ES/wre.

July 13, 1943. w. E. SHORE REFRIGERANT COMPRESSOR 4 SheetS-Sheet 2 F'iied March 29, 1940 A v, 5 I

July 13, 1943. w. E. SHORE REFRIGERANT COMPRESSOR Filed March; 29, 1940 4 Sheets-Sheet 3 In V'eh Cor. Wil/iam 1 Share,

w. E. SHORE REFRIGERAN'I COMPRESSOR July 13, 1943.

Filed March 29, 1940 4 Sheets-Shut 4 Irn/enlor William ES/IOIC.

as I

v Patented Jul 13,1943

UNITED STATES "PATENT OFFICE ammonium comranssolt William E. Shore, We: New Brighton, Staten Islam Application March 29, 1940, Serial No. 326,704 15 clai s.- (01. 230-439) The present invention relates to the type of electrically operated refrigerant compressors in "which the operating mechanism is hermetically sealed within an enclosing casing, and the principal objects of the invention'are to provide a mechanism of extremely high eiiiciencyin which the parts ;are sot constructedand balanced that vibratory inertia and the resultant noise and wear are reduced to a negligible quantity.

A further and very important object of this invention is to effect a substantial transfer of the mechanical heat generated in the compressor as well as the heat of compression of the refrigerant so that such heat willbe readily dissipated from the externally exposed surfaces of sist. in the novel construction and arrangement within-an enclosed electrical stator of a rotor including a compressor cylinder mounted upona fixed axis and a rotative compressor element mounted upon a fixed axis eccentric to the axis of said cylinder, said cylinder carrying an abutment axially slidable in said compressor element and directing the inilow ofthe refrigerant'to the cylinder and dividing the intake and compression areas and also directing'the discharge .of the compressed refrigerant. A further and important feature of the invention resides in the novel manner of individually balancing the separate rotative members of the composite rotor.

A still further important feature resides in the novel manner of circulating the lubricant to the bearing surfaces and through a plurality of 'ducts adjacent to the outer casing to eil'ectthe transfer and dissipationof heat generated or acciiinulated within theroton- I -In' the accompanying drawings Figure lls a longitudinal mid-sectional 'view of an electrically operated sealed refrigerant compressor unit constructed in, accordance with this invention -Figure 2 is' a partial fragmentary cross sectional view taken on the line 2-2 of Figure 1.

Figure 3 is a diagrammatic plan and frag.- mentary sectional view of the rotor showing the abutment for dividing the intake and compression areas of the cylinder arranged in theneutral position at the end of discharge and the commencement of intake. v

Figure-415a view similar to Figure 3 showing the relative position of the abutment at approximately one quarter of a revolution from the position illustrated in Flgure 3.

Figure 5 is a viewvslmil'ar to Figure 4 showing the relative position of the parts when the abutment is in a position diametrically opposite to that shown in Figure 3. Figure 6 is a view similar to Figures 3,4 and 5 illustrating the abutment in a position diametrically opposite to the position illustrated in Figure4.- y

Figure 7 is a horizontal sectional view of the rotor taken on the line.I--1 of Figure 1 and showing the arrangement of the reirigerant intake passages to the cylinder.-

Flgure 8 is a horizontalsecti'on' of the rotor taken on the line a-a or Figure i illustrating the arrangement of the discharge passages from the compressor cylinder.

Figure 9 is ahorizontal sectional view through the rotor taken on the line 8-9 oi Figure 1.

Figure 10 is an end view of the rotor showin a;modiiied arrangement of balancing means.

Figure 11' 'isa side elevational view of the abutment memberof the rotor removed from the cylinder.

Figure 12 is c an end elevational view of the abutment shown in Figure 11. v Figure 13 is a top plan'viewlof the bottom end member or the compressor cylinder shown in part horizontal section on the line l3-l3 of Figure Figure 14 is an elevational view of the bottom end of-the compressor cylinder member taken in part section on the line lQ-ll of Figure 13, also showing in partsection a portion of the rotary compressor member within the com-- v pressor cylinder.

Figure-15 is a fragmentary plan view and part section of the compressor cylinder showing the arrangement of the emergency-or overload discharge passage from the cylinder to the mechanism illustrated in Figures 13 and 14.

Figure 16 is an elevational and-part mid-sectional view illustrating a modification oi the cas ing structure illustrated in Fisure' 1.

--It is knownto'those skilled in the m that a great variety of hermetically sealed pumps and compressors for the handling of liquids, gases and refrigerants, have been proposed in which numerous forms of eccentric and' reciprocating piston devices are used, and it is recognized that different means for counter-balancing the operating members have been proposed.

It is the purpose of this invention to provide a structureof remarkably simple form which will accomplish the object which it is desired to attain in devices of this class, and, with the consideration pertaining to mechanical balanced unity, the present invention provides improved balance methods and means in a rotary compressor wherein each rotatable member is individually balanced, each concentric to its specific operative axis with each specific axis considered individual to each other and all collectively .rotating in such a manner as to practically eliminate compression vibratory impulses and mechanical unbalance.

Referring to the accompanying drawings, the outer casing l is of substantially d me shape and encloses a motor frame housing 2 which is provided with a plurality of longitudinal channels 3 extending from end-to-end thereof and spaced apart around the periphery. A base member 4 closing the bottom end of the casing I is preferabl hermetically sealed within the casing by flanging the rim of the casing inwardly against a suitable packing 5. The base member abuts the frame housing 2 securing same snugly against a shoulder 6 formed in the upper part of the side wall of said casing.

A motor stator structure Lis'rigidly mounted within the frame housing 2 at its upper end, be-

secured between the flanges 23 and 29. The preferable method of constructing the electrical element of "the rotor is to form the lamination stack witha plurality of holes 3| extending from top to bottom of the stack, and the resistance flanges and 29 and the connecting inductors 2| extending through the holes are die-cast from suitable metal and the structure thus forms a squirrel-cage type of rotor, which, after being properly machined and balanced, may be pressed on to the periphery of the cylinder and the edges of the flanges 28 and 29 may be pressed or rolled over the flanged cylinder end members, thereby tightly clamping the latter against the ends of the cylinder and retaining the unit in assembled form. It is important to note that this construction provides a continuously smooth outer surface free from clamping bolt projections, thereby .tance .where'the unit is'to be operated in subing supported by an inwardly extending flange 8.

thereon acollar l5 which is provided with a flange It at its lower end and has an enlarged upper fiange portion 11 which fits snugly within a cupped recess l8 formed in the top'of the casing I. The flange I1 is provided with a plurality of holes is extending downwardly therethrough and opening at the bottom end into the interior of the casing I. r

A washer "encircles the shaft ,at the inner end of the hub II and a bearing bushing 2| surrounds said shaft above said end-bearing washer.

A flange member 22, which forms the lower end of the compressor cylinder, encircles the bushing 2| and is formed with a peripheral concentric recess 23 in which a tubular shaped cylinder 24 is mounted. A flange member", similar in construction to the flange 22, closes the upper end of the cylinder 24 and has a bushing 20 encircling a portion of.the shaft l3, the upper end of said flange and bushing being a short distance from the flange it of the collar IS. The entire cylinder structure is thus frotatably mounted concentricallyof the shaft l3.

- -The electrical element of the rotor is. here shown in the form of laminations 21 which surroun the peripheryof cylinder 24am! are merged relation to a body of lubricating oil.

The rotor when thus assembled is rotatably mounted within the stator 9.

The shaft I3 is formed with-an eccentric portion 32 intermediate of its length, which is arrangedbetween the inner faces ofthe cylinder end flanges 22 and 25, and a cylindrical rotor piston 33 encircles and is lournalled upon the eccentric 32 in such a manner that the perimeter of the piston engages the inner wall of the cylinder 24 in line with the greatest distance of eccentricity of the eccentric 32 from the main portion of the shaft II, the remainder of the perimeter of the piston being separated from the cylinder wall.

The piston 33 is formed with a vertical slot :4 I

extending radially inward from the perimeter and extending from end-to-end thereof and the opposing faces of said slot are parallel;

An abutment in the form of a substantially rectangular shaped block 3." is slidably mounted within the slot 34 and has mounted upon its ends, forming a part thereof, cylindrical journal members 36 and 31. These Journal members are rosize of the blade or abutment.

I have determined through extensive experimentation that notpnly isltimportant in a compressor of'the type set forth, to maintain the axisof oscillation of the abutment within the periphery of the eccentrically mounted piston, but also to permit little or no sliding contact of. the ends of the abutment with the inner surfaces of the cylinderends due to the detrimental binding or wearing action against such surfaces.

I therefore purposely form the trunnion portions 38 and 31 oisuch size that they overlap. all or substantially all of what.wouid otherwise be exposed end faces of the abutment and in the form shown it will be seen that thetrunnions extend well beyond at least three sides of the abutment in planestransversely of the axis of oscillation, so that they provide extensive sealing and positioning contact with the,ends of the rotary p ton.,

I prefer in any case to so relatively proportion the abutment portion and the trunnions that the cross sectional area of each trunnion will be greater than the cross sectional area of the abut- .ment or so that the end thrust surface presented by each trunnion will be greater than or will replace the otherwise exposed end surfaces of the abutment proper even to the exclusion thereof. The outward longitudinal face of the rectangular abutment member 35 is held by the journal ends 36 and 31in engaging or sealing contact with the inner peripheral. surface .o'f the cylinder 24, and said contact being lengthwise of the abutment, is concentric to the axis of the journal ends thereof, so that the abutment may roll and maintain its operating contact with the cylinder surface.

It will be understood that as the rotor is caused to rotate through the influence of the electrical forces acting between the stator and rotor,.the

3 of the shaft. is to discharge through the radial channels I into the interior of the chamber enclosed by the casing l.

Upon the application of electric energy to the stator I the rotor will be caused to rotate the direction of rotation being indicated by the arrow in Figures 3, 4 etc., andthe cylinder 24 with its flange ends 2 2 and 25 rotates about the main axis of the shaft I3.

It will be understood that, as the abutment has its journal ends 36 and 31 mounted in the bearings 88' and I! in the said flange ends, the

outward rounded edge of the abutment is held in contact'with the inner wall of the cylinder'and is carried with the cylinder in its rotating movement.

cylinder will rotate upon its bearings formed by the bushings 2i and 26, and it will be seen that there willbe an unbalanced condition due to the location of the abutment member 35 between its journals. i

This condition may be corrected by forming recesses 40 in one or both of the cylinder end flanges 22 or 25 and placing in these any suitable substance which will effect a'balance, or, it may be found desirable to apply'to one. or both of the hubs of the flanges 22 or 25, if the rotor is not submerged in a fluid lubricant, an eccentric balance member illustrated particularly in Figure 10. r

An intake conduit 42 leading from the refrig erating system is connected to a central'oriflce 43 leading through the hub of the base 4, and the shaft I3 is provided with a central orifice 44 in the shaft I! which leads to aplurality ofv radial channels 45 which extend outwardly to a'peripheral channel 46 which extends completely around the eccentric portion of'the shaft, as shown particularly in Figure 7 and in elevation in Figure 1.-

A peripheral channel 41, which extends only part way around the circumference of the eccentric portion of the shaft, is spaced from the channel 46 and is connected by radial channels The, engagement of the flat, side faces of the abutment IS with the side walls of the slot 34 in the rotor piston 33 causes the piston to rotate aboutthe axis of the eccentric portion 32 of the shaft ii in harmony with the rotation of the cylinder, and the cylinder chamber is in constant communication with the intake to the passages in the shaft and the channel it extending through the rotor piston. i

The movement of the cylinder and the abutment-from the position indicated in Figure 3 to the position indicated in Figures 4 and 5, creates .a suction to draw refrigerant gases into the cylinder chamber from the refrigerating system.

This intake actio'n continues throughout the completion of each revolution of the cylinder and, as the abutment passes the line of contact between the rotor piston and the cylinder wall the gases that have been previously drawn into the cylinder are compressed until the piston reaches approximately the position shown in Figs. 5 and 8 when the channel 52 moves into communication with the peripheral channel 41 in the shaft and the gases which have been compressed are discharged to the channel 41 and radial channel 48 into the central discharge orifice 49 in the shaft which discharges, as previously described, through the radial channels 50. r v I It will be appreciated that in the operation of the rotor the piston rotates in unison with the cylinder about its'eccentric axis and it operates with a relative harmonic movement and the abutment in the course of rotation of the cylinder 48 witha central orifice 49 extending upwardly through the shaft and connecting with radial channels 50 which open outwardly from the shaft between the top of the hub of the upper cylinder end 26 and the flange l8 ofithe collar I! mounted inthe casing I.

On reference particularly to Figure '1, it will be seen that the peripheral intake channel 40 in the eccentric portion of the shaft I3 is in constant communication with a channel 5| leading through the piston member 33 at one side of the slot 34 therein, which thus forms a communicating connection with the interior of the cylinder on the intake side of the abutment member 35.

A channel 52, arranged in the rotor piston 33 at the opposite side of the abutment slot 34 to i that on which the channel. Si is arranged, communicates with the peripheral discharge channel 41 periodically inthe operation of the machine and permits the refrigerant compressed within the cylinder to flow inwardly and upwardly through the central channel in the upper portion slides radially in the slot 34.

The mechanism as herein described is immersed in a bath of oil which, when the machine is at rest, has its upper level slightly beloig. the

top of the stator indicated by the line 0- -0 of Figure 1, and, as the compressed refrigerant is discharged into the interior oi the casing I above this oil level, thereis a pressure appliedto the oil.

An opening 58 is arranged in the flange member 22 at the bottom of the recess 38 in which the lower abutment journal is mounted and oil is forced through the opening 53 to lubricate the I journal.

' A diagonally arranged oil duct extends upwar'dly through the journal end II and it directs oil into the inner end of the slot 34 in the piston back of the abutment. A corresponding diagonal, oil duct 55 extends through the upper I journal and conducts on from the slot 34 to lubricate the journal recess 39. j

A small oil duct 50 extends through the wall of the rotor piston and conducts oil from the slot 34 to lubricate-the shaft, the surface of said shaft having a spiral oil groove 51 cut therein to distribute oil to the upper bearings.

34 forces a. film of oil outwardly either side of the ..-abutment to both lubricate the abutment and also to lubricate the inner wall of the cylinder.

' It will of course be appreciated that a certain amount of lubricating oil will be dischargedfrom the cylinder with each cycle of operation but this will flow laterally from thedischarge open- -'out through the ultimate discharge of the compressed regfrigerant, a fan member 58 isprovided in the form of a collar having a plurality of radial vanes which is secured on the hub of the upper cylinder flange end 25, the said vanes extending into the path of discharge from the radial discharge channelsSO.

It will be understood that heat accumulated within the cylinder or developed through mechanical operation will be absorbed by the body of oil surrounding the rotor, and in order to effect the dissipation of such heat the stator is provided with the openings 9 through which the oil may flow, and when the machine is in operation there will be a considerable displacement effected and the oil level will rise-until it flows from the top of the openings 9 over the frame 2 and down through the peripheral longitudinal channels 3.

Openings 59 are arranged between the base 4 and the housing 2 at the bottom end of the channels 3 to permit a free circulation of the oil. Heat absorbed by the oil surrounding the inner portions of the mechanism will be carried outwardly with the circulating oil and will be dissipated by conduction and radiation from the outer surface of the casing l.

The oil pressure within the interior of the slot flange 22 and communicates with the inner end 7 of the cylinder 43.

In the event of oil or other liquids filling the compression side of the cylinder chamber at the beginning of a compression movement the discharge port 52 would of course be closed. Consequently any force exerted to turn the compressor body to compress or discharge the noncompressible liquid therein, would form an extreme overload and strain. In such an event the liquid under pressure would flow through the port 64 into the relief cylinder, forcing the piston valve 65 inwardly until communication would be established between the said port 64 and the main duct 86 in the bottom of the flange and the pressure in the cylinder would therefore be immediately released, the oil or liquid being forced from the main cylinder, and immediately this pressure/is relieved the oil under pressure within the casing will flow in through the small duct 6'! to the inner end of the piston valve 65, forcing it outwardly in addition to a natural operation under centrifugal force. nism is extremely simple and obviates many difficulties that are found in springloaded types of relief valves.

A discharge conduit 60 extends outwardly from I the recess l8 in the top of the casing 2.

.It has been previously described that the composite member forming the cylinder will be balancedby the arrangement of extra weight in the openings or by the adjustment of the eccentric members 4|, and as the rotor piston is unbalanced by the cutting of the slot 34 therein, it is found necessary to balance this element to remove unbalance inertia. This is accomplished in a very simple manner by boring holes 8| therein to,remove the required amount of metal from the side of the piston opposite to the abutment slot and plugs 6| of a lighter material are preferably placed in the holes '60 so that oil will not lodge therein to disturb the balance.

"In order to ensure the most active circulation I of the oil in its function of dissipating heat accumulated or generated within the1machine a slightly to one side of the journal recess 38 of the abutment. The outer end of the cylinder 63 communicates with the main cylinder chamber through a port 64 immediately adjacent to and on the compression side of the abutment, 35 and within the the cylinder 63 is arranged a small piston valve 65. A duct 66 extending upwardly through the bottom end of the flange 22 enters the relief cylinder 63 intermediate of its length An important feature in the construction of device herein shown is, that in providing for the lubrication of the contacting moving parts, the pressure within the casing I being exerted against the bath of oilsurrounding the mechanism, forces'oil through the passages described into the slot 34. in the piston back of the abutment, and as the-compressor operates from the position illustrated from Figures 3 to 4 and from 4 to 5, the oil being fed to the slot 34 is at a higher pressure than the refrigerant in the compression chamber and suction chamber. quently there will be no leakage of compressing fluid from the high side of, the abutment member 35 to the low side through the oilentrapped behind said abutment, but as the compressor moves from the position illustrated in Figures 5 and 6 to that shown in Figure 3, the passage 52 is opened to the cut-ofl passage 41 in the shaft. The compression chamber is then opened and balances the pressure within the main casing, and the lubricant pressure in the slot 34 is equalized.

' The maintenance of pressure upon the oil bath in which the parts operate causes a continuous feed of oil to be effected to all the working parts, the pressure within the slot 34 feeding oil to the flat contacting surfaces of the abutment and the rotor and also feeding oil through the oilduct in the piston to the oil groove 51 in the shaft. It will of course be understood that oil will seep downwardly along the shaft'surfaces to lubricate thelower joumal'of the bushing 2|.

. The circulation'of the oil upwardly through the ducts 3 in the stator to flow downwardly derstood that the heat contained in the various elements, including the body of oil, holds the temperature for aconsiderable period of time, so that a normal workingtemperature is mainand a smaller duct 61 extends through said tained in the entire motor compressor mechanism.

Such a relief mecha,'

Conse- It will of course be understoodthat, if under modify the external casing structure and a modiflcation'is illustrated in Figure 16. In this conwithin the casing l" and is provided with -;a flanged edge 89 which rests upon the motor housing 2. The ported collar i is fitted withinthe flange of the cap 68 and a coil compression spring II is interposed between the cap 68 and the outer casing i.

The upper support of the shaft I3 is thus mounted in the bell cap 68 instead of directly in the outer shell casing and such construction may obviate any distortionofthe motor frame and compressor shaft which' might possibly occur in the sealing of the outer casing and motor frame, as'illustrated 'in Figure 1.

It is important to note the peculiar co -opera tive'movement between the cylinder and the rotary piston. The cylinder rotates concentricale 1y of the main axis of the shaft i3 and, as the abutment member 35 is mounted between fixed pivots in the cylinder ends, the abutment is carried with the cylinder.

The abutment extends radially into the slot] 34 in the piston which is of smaller diameter than the interior of ,the cylinder and rotates concentrically with the axis 'of the eccentric portion of the shaft,

It will be noted on reference to Figure 3 that the abutment is shown in central alignment with the line 33-)! and the abutment is then in its fully recessed position in the slot 34 with the piston practically touching the inner wall of the cylinder.

As the cylinder continues its rotation the piston member maintains its line of contact with the cylinder wall on the line PQ, Figures 4, 5'

and 6, while the remaining portion of the perimeter recedes away from and again'approaches the cylinder wall, and, because of the fact that the piston is carried around a complete revolution with each revolution of the cylind r due to the contact of the abutment with the sid s of the introduced or cooling coils struction a cup or bell-shaped cap 68 isarranged slot in the piston, there is a change of speed due to the difference in diameter of the piston and cylinder in their peripheral relation.

It will be observed that the rotor surface, as the slot 34 passes the line P-'-X, will be movin in unison with the cylinder, but as the slot 34,

passes the position shown in Figure 5, that is, diametrically opposite the line P-X, the rotor surface will be moving slower than the cylinder wall. There is therefore a relative increasin and decreasing relationship of the speed between .the rotor and the cylinder. If the cylinder were stationary it wouldbe noticeable by vibration even though the rotorwas perfectly balanced. A similar action appears in the sliding vane pump. which is very noticeable, but because of the cylinder in the present construction being propelled by a flexible magnetic rotation, some of the harmonic movements defined is taken up by the compressor body and themotor rotor and is distributed among the rotating members. The

slight difference in movement is therefore dis-- sipated among the several members without creating any distinct unharmonic condition.

' 'a shaft rigidly mounted axially of said casing Fromthe foregoing description it will be readily appreciated that extremely fine machining of the parts will not be necessary in order to accomplish the desired eflect anda very efllcient apparatus is produced which will be extremely economic in its operation and will occupy the very minimum of space. Further, it operates without vibration and without noise.

An important feature in the operation of this device is that the lubricant entrapped in the 'slot 34 back of the abutment 35 is subjected to sealed casing enclosing an electrical'stator and a shaft fixed from rotation in said casing, an electric motor rotor including a compressor cylinder rotatably mounted on said shaft and'surrounded by said stator, a cylindrical rotary piston eccentrically mounted within said cylinder and having sealing contact therewith at one side "thereof, a member having journal portions at each end thereof journalled in said cylinder at both ends thereof for oscillation about an axis permanently disposed within the periphery of said rotary piston and having blade portion intermediate said journal portions extending inwardly from the inner periphery of the cylinder and operatively'engaging said eccentric piston to rotate same in unison with said cylinder, and said journal portions projecting beyond the piston to form a seal .the. cross sectional area of each of the journal portions of said member being substantially greater than the cross sectional area of said blade portion, means for direeting the inflow of refrigerant to the cylinder at one side of said member, and means for controlling the outflow of the compressed refrigerant from said cylinder-on the opposite side of said member. V

2. A device as claimed in claim 1 in which the means carried by the cylinderand operatively engaging the eccentrically mounted piston comprises an abutment journalled at its ends in the ends of the cylinder and having its outward edge engaging in sealing contact with the inner periphery of the cylinder and having parallel walls engaging in sliding contact with said eccentric piston, said piston having a radial slotfor sealing and engaging the parallel walls of said abutment, the journal portions of said abutment each presenting inwardly andoutwardly facing surfaces respectively engaging the ends of the piston and the ends of the cylinder in end thrust and positioning contact and representing substantially' the only end contact area between said abutment and said piston and cylinder ends.

3. A refrigerant compressor comprising a an electric motor stator mounted in said casing,

having an eccentric portion intermediateof its length, a Journal encircling said shaft, at each end of saidjecccntric portion, flange members mounted .on said Journals, 0. cylinder arranged between said flange members and sealed thereto,

an electricalrotor embracing said cylinder and ope'rativeLv connected to and surrounded by said stator, an annular piston encircling the eccenshaft mounted within said flange members and having sealing engagement therewith, an abutment secured in' said flange members and engaging the interior wall of the cylinder in sealing contact and having sliding engagement with said piston to operate same in unison with said cylinder, the outer ends of said electrical rotor having reduced end portions turned inwardly over the ends of said flange members in a smooth continuous circumferential clamping relation to retain said cylinder, flanges and electrical rotor together in a firmly assembled unit free of rotation-obstructing protuberances, said unit being submerged in part at least in the body of lubricant in said casing, means for directing a refrigerant medium into the, intake side of the cylinder at one side of said abutment,

and means for directing compressed refrigerant from the discharge side of said cylinder on the other side of said abutment.

4. A refrigerant compressor comprising a sealed casing enclosing an electric motor stator and containing a body of lubricant, ashaft rigidly mounted in said casing concentrically of said stator and having an eccentric portion, a pair of cylinder ends rotatably mounted on said shaft and having balancing weight members recessed thereinto to balance said ends and parts connected therewith and being free of projection to minimize frictional resistance with the body of lubricant, a cylinder connecting said ends, an

, ancing of said piston independently, means for directing a refrigerant medium to the cylinder at one side of said abutment, and means for directing the compressed refrigerant medium from the cylinder on the opposite side of said abutment.

5. In a refrigerant compressor, a sealed casing enclosing an electric motor stator, a shaft fixed from rotation in said casing concentric with said stator and having an eccentric portion, a cylinder rotatably mounted on said shaft within said stator, an electric motor rotor surrounded by said stator and operatively connected to said cylinder, an annular piston encircling the eccentric portion of said shaft, an abutment carried by said cylinder and extending in operative engagement with said piston to rotate same in unison with the cylinder, means for directing the inflow of refrigerant to the interior of the cylinder at one side of said abutment, means for controlling the outflow of compressed refrigerant from the cylinder on the opposite side of. said abutment, and means for releasing an overload in the compression side of the cylinder, including a relief discharge port, a piston valve normally sealing said port and arranged to be acted upon by an abnormal force of compression in opsurrounded by said stator and including a compressor cylinder, an annular piston operating in said ,cylinder, means for directing refrigerant into the intake side of said cylinder, and means for directing compressed refrigerant from the discharge side of said cylinder into the interior of said sealed casing, the combination therewith of a bell cap arranged within the casing supported on the motor housing and having dissealed casing enclosing an electrical motor stator and a shaft fixed in said casing, an electric motor rotor surrounded by said stator and, incluffling a compressor cylinder having closed ends and rotatably mounted on said shaft, a cylindrical rotary piston eccentrically mounted within said cylinder and having sealing contact therewith at one side thereof, a member having journal portions journalled in said cylinder for oscillation about an axis permanently disposed within the periphery of said rotary piston and having an intermediate blade portion extending inward-- 1y from the inner periphery of the cylinder and operatively engaging said eccentric] piston to rotate same in unison with said cylinder, said journal portions of said member being arranged in bottomed journal recesses in the ends of the cylinder wall and presenting therewith end thrust and positioning contact areas at each end.

ofsaid blade portion greater than the cross-sectional area of the said blade portion, means for directing the inflow ofrefrigerant to the cylinder at one side of said blade member, and means for controlling the outflow of the compressed refrigerant from said cylinder at the opposite side of said blade member.

8. A compressor as claimed in claim '7 in which the Journal portions of said member comprise trunnions so constructed and arranged in relation to the blade portion that they extend in planes transversely of the axis of oscillation well beyond at least three sides of the blade portion in extensive sealing relation to the ends of the rotary piston.

9; A compressor as claimed in claim 7 in which the journal portions of said member comprise trimnions so constructed and arranged in relation to the blade portion that they extend in planes transverselyof the axis of oscillation well beyond at least three sides of they blade portion in extensive sealing relation to the ends of the rotary piston, said trunnions overlying substantially the entire end areas of said blade portion except for local areas immediately djacent the inner peripheral surface of said cylinder.

position to centrifugal force to release the overload through said port, and means for applying the force of the compressedmediumto said pis- 10. In a compressor of the class described, in

combination, a cylinder unit rotatable about a .flxed axis and having fluid inlet and'discharge ton valve to supplement the centrifugal closing force thereof.

6. In a refrigerant compressor comprising a sealed casing forming-a motor housing enclosing an "electric motor stator rigid therewith, aflxed and fixed to-sa'id casing; an electric motor rotor mounted on said shaft 75 like trunnion portions at the ends, said cylinder I having .bottomed cylindrical Journal bores .re- .ceiving said pbton-like trunnions, means for dimeans. a rotary piston rotatable with-said cylinder about an axis eccentric to said cylinder and having a slot in qne side, an abutment member slidably fitting in said slot and having pistonrecting fluid under substantially uniform pressure to the' ends of said respective cylindrical journal bores to provide a substantially balanced end pressure between said piston-like trunnions and the respective bottoms of said cylinders.

11. A compressor as claimed in claim in which said compressor is sealed within a casing having a body of lubricant and has the discharge means connected with the casing interior, one of said cylindrical journal bores being directly connected axiallywith the bodyoi lubricant in said casing and the other of said bores being connected with the first-mentioned bore through said slot.

12. A compressor as claimed in claim 10 in which said compressor is sealed within a casing having a body of lubricant a'hd has the discharge means connected with the casing interior. one of said cylindrical Journal bores having an axial opening to expose the outer end '01- the respective piston-like trunnion to the working pressure 01' the lubricant body, the latter trunnion having a passage leading obliquely from the outer axial region and opening into said piston slot at one end inwardly oi the abutment therein, and the other trunnion being formed with a passage leading from the other end of said piston slot obliquely through the said other trunnion to the axial region of the respective journal bore.

and adapted to be uncovered by the movement of the valve to open communication between the compression side 01 the cylinderv and the interior of the sealed casing, and a port connecting the inner end'oi! said valve chamber with the interior of the sealed casing and Iorming a passage to conduct the pressure of compression in the casing to the valve chamber to operate the valve to close the cylinder port. 10

the cylinder, means -i'or directing the inflow oi refrigerant to the interior of the cylinder at one side of said abutment, means for controlling the 13. In a refrigerant compressor, a sealed casing enclosing an electric motor -stator, -ashaft fixed from rotation in said casing concentric with said stator and having an eccentric portion, a

'cylinder rotatably mounted on said sha!t.within said stator, an electric motor rotor surrounded by said stator and operatively connected to said cylinder, an annular piston encircling the eccentric portion of said shaft, an abutment carried by said cylinder and extending in operative engagement with said piston to rotate same in unison with the cylinder, means tor directing the inflow of refrigerant to the interior of the cylinder at one side of said abutment, means for directing the outflow of compressed refrigerant from the cylinder into the interior of said casing at ,the'opposite side of said abutment, the cylinder structure being provided with a cylindrical valve chamber having communication with the compression side 01' thecylinder chamber, a piston valve operable in said valve chamber, a port intermediate 0! the length of said valve chamber 50 outflow oi. compressed refrigerant to the interior or the sealed casing from the cylinder at the opposite side of said abutment, a cylindrical valve chamber being radially arranged in the lower cylinder end, said valve chamber having a portat its outer end communicating with the compression side 01' the cylinder and having a port at its innerend communicating withv the interior of the sealed casing and also having a port arranged intermediate of its length communicating with the interior of the cylinder casing, anda piston valve'slidably arranged within said radial valve chamber and adapted to be maintained in its outward sealing position through the centrifugal action of the cylinder in additionto pressure from the interior of the casing flowing through V the port communicating with the inner end of the valve chamber.

' 15. In a compressor of the class described, a

cylinder structure rotatable about a fixed axis, a

piston eccentrically co-operating interiorily with said cylinder, and an electrical induction rotor embracing said cylinder and formed with int lr l flanges turned inwardly into clamping engagement with the cylinder structure.

WIILIAM E. SHORE. 

